From [[Wikipedia: Network File System|Wikipedia]]: Network File System (NFS) is a distributed file system protocol originally developed by Sun Microsystems in 1984, allowing a user on a client computer to access files over a network in a manner similar to how local storage is accessed.

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From [[Wikipedia: Network File System|Wikipedia]]:

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: ''Network File System (NFS) is a distributed file system protocol originally developed by Sun Microsystems in 1984, allowing a user on a client computer to access files over a network in a manner similar to how local storage is accessed.''

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This article covers the installation of NFSv4.

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== Installation ==

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==Installing==

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Both client and server only require the [[Pacman|installation]] of the {{Pkg|nfs-utils}} package.

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{{Note|It is HIGHLY recommended to use a time sync daemon on ALL nodes of your network to keep client/server clocks in sync. Without accurate clocks on all nodes, NFS can introduce unwanted delays!}}

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Both client and server only require the [[pacman|installation]] of the {{Pkg|nfs-utils}} package.

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The [[NTP]] system is recommended to sync both the server and the clients to the highly accurate NTP servers available on the Internet.

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{{Note|It is HIGHLY recommended to use a time sync daemon on ALL nodes of your network to keep client/server clocks in sync. Without accurate clocks on all nodes, NFS can introduce unwanted delays! The [[NTP]] system is recommended to sync both the server and the clients to the highly accurate NTP servers available on the Internet.}}

==Configuration==

==Configuration==

===Server===

===Server===

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==== ID mapping ====

==== ID mapping ====

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Edit {{ic|/etc/idmapd.conf}} and set the {{ic|Domain}} field to your domain name.

Edit {{ic|/etc/idmapd.conf}} and set the {{ic|Domain}} field to your domain name.

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Nobody-Group = nobody

Nobody-Group = nobody

</nowiki>}}

</nowiki>}}

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==== File system ====

==== File system ====

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{{Note|For security reasons, it is recommended to use an NFS export root which will keep users limited to that mount point only. The following example illustrates this concept.}}

{{Note|For security reasons, it is recommended to use an NFS export root which will keep users limited to that mount point only. The following example illustrates this concept.}}

Define any NFS shares in {{ic|/etc/exports}} which are relative to the NFS root. In this example, the NFS root will be {{ic|/srv/nfs4}} and we will be sharing {{ic|/mnt/music}}.

Define any NFS shares in {{ic|/etc/exports}} which are relative to the NFS root. In this example, the NFS root will be {{ic|/srv/nfs4}} and we will be sharing {{ic|/mnt/music}}.

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{{bc|# mkdir -p /srv/nfs4/music}}

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# mkdir -p /srv/nfs4/music

Read/Write permissions must be set on the music directory so clients may write to it.

Read/Write permissions must be set on the music directory so clients may write to it.

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Now mount the actual target share, {{ic|/mnt/music}} to the NFS share via the mount command:

Now mount the actual target share, {{ic|/mnt/music}} to the NFS share via the mount command:

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{{bc|# mount --bind /mnt/music /srv/nfs4/music}}

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# mount --bind /mnt/music /srv/nfs4/music

To make it stick across server reboots, add the bind mount to {{ic|fstab}}:

To make it stick across server reboots, add the bind mount to {{ic|fstab}}:

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==== Exports ====

==== Exports ====

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Add directories to be shared and an ip address or hostname(s) of client machines that will be allowed to mount them in {{ic|exports}}:

Add directories to be shared and an ip address or hostname(s) of client machines that will be allowed to mount them in {{ic|exports}}:

{{hc|/etc/exports|<nowiki>

{{hc|/etc/exports|<nowiki>

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/srv/nfs4/ 192.168.0.1/24(rw,no_subtree_check)

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/srv/nfs4/ 192.168.0.1/24(rw,fsid=root,no_subtree_check)

/srv/nfs4/music 192.168.0.1/24(rw,no_subtree_check,nohide) # note the nohide option which is applied to mounted directories on the file system.

/srv/nfs4/music 192.168.0.1/24(rw,no_subtree_check,nohide) # note the nohide option which is applied to mounted directories on the file system.

</nowiki>}}

</nowiki>}}

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Users need-not open the share to the entire subnet; one can specify a single IP address or hostname as well.

Users need-not open the share to the entire subnet; one can specify a single IP address or hostname as well.

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See {{ic|man exports}} for detailed settings information.

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For more information about all available options see {{ic|man 5 exports}}.

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If you modify {{ic|/etc/exports}} while the server is running, you must re-export them for changes to take effect:

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# exportfs -rav

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==== Starting the server ====

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[[Daemons|Start]] {{ic|rpc-idmapd}} and {{ic|rpc-mountd}} services. If you want it running at boot time, enable it. Note that these units require other services, which are launched automatically by [[systemd]].

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For more information about all available options see {{ic|man 5 exports}}.

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==== Firewall configuration ====

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If you modify {{ic|/etc/exports}} while the server is running, you must reexport them for changes to take effect:

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To enable access through a firewall, tcp and udp ports 111, 2049, and 20048 need to be opened. To configure this for [[iptables]], edit {{ic|/etc/iptables/iptables.rules}} to include the following lines:

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{{bc|# exportfs -ra}}

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====Starting the server====

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{{hc|/etc/iptables/iptables.rules|<nowiki>

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-A INPUT -p tcp -m tcp --dport 111 -j ACCEPT

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-A INPUT -p tcp -m tcp --dport 2049 -j ACCEPT

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-A INPUT -p tcp -m tcp --dport 20048 -j ACCEPT

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-A INPUT -p udp -m udp --dport 111 -j ACCEPT

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-A INPUT -p udp -m udp --dport 2049 -j ACCEPT

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-A INPUT -p udp -m udp --dport 20048 -j ACCEPT

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</nowiki>}}

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The services for the NFS server are {{ic|rpc-idmapd.service}} and {{ic|rpc-mountd.service}}.

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To apply changes, restart {{ic|iptables}} service.

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Start them and configure them to start at boot. Read [[Daemons]] for more details.

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=== Client ===

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Note that these units require others, which are launched automatically by [[systemd]].

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Clients need {{Pkg|nfs-utils}} to connect, and to avoid an approx 15 seconds delay with an accompanying error in dmsg that reads, "RPC: AUTH_GSS upcall timed out," users will need to start {{ic|rpc-gssd}} service on any client.

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===Client===

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{{Note|NFS4 servers do not need to run this service.}}

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Clients need {{Pkg|nfs-utils}} to connect, but no special setup is required when connecting to NFS 4 servers.

Using [[fstab]] is useful for a server which is always on, and the NFS shares are available whenever the client boots up. Edit {{ic|/etc/fstab}} file, and add an appropriate line reflecting the setup. Again, the server's NFS export root is omitted.

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=====/etc/fstab Settings=====

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Using [[fstab]] is useful for a server which is always on, and the NFS shares are available whenever the client boots up. Edit {{ic|/etc/fstab}} file, and add an appropriate line reflecting the setup.

{{Note|Additional mount options can be specified here. Consult the NFS man page for further information.}}

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{{Note|Consult the NFS and mount man pages for more mount options.}}

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Some additional mount options to consider are include:

Some additional mount options to consider are include:

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* {{ic|1=rsize=8192}} and {{ic|1=wsize=8192}}

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; rsize and wsize: The {{ic|rsize}} value is the number of bytes used when reading from the server. The {{ic|wsize}} value is the number of bytes used when writing to the server. The default for both is 1024, but using higher values such as 8192 can improve throughput. This is not universal. It is recommended to test after making this change, see [[#Performance tuning]].

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* {{ic|1=timeo=14}}

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* {{ic|1=intr}}

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; timeo: The {{ic|timeo}} value is the amount of time, in tenths of a second, to wait before resending a transmission after an RPC timeout. After the first timeout, the timeout value is doubled for each retry for a maximum of 60 seconds or until a major timeout occurs. If connecting to a slow server or over a busy network, better performance can be achieved by increasing this timeout value.

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The {{ic|rsize}} value is the number of bytes used when reading from the server. The {{ic|wsize}} value is the number of bytes used when writing to the server. The default for both is 1024, but using higher values such as 8192 can improve throughput. This is not universal. It is recommended to test after making this change.

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; intr: The {{ic|intr}} option allows signals to interrupt the file operation if a major timeout occurs for a hard-mounted share.

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The {{ic|timeo}} value is the amount of time, in tenths of a second, to wait before resending a transmission after an RPC timeout. After the first timeout, the timeout value is doubled for each retry for a maximum of 60 seconds or until a major timeout occurs. If connecting to a slow server or over a busy network, better performance can be achieved by increasing this timeout value.

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; _netdev: The {{ic|_netdev}} option tells the system to wait until the network is up before trying to mount the share. systemd assumes this for NFS, but anyway it is good practice to use it for all types of networked filesystems

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The {{ic|intr}} option allows signals to interrupt the file operation if a major timeout occurs for a hard-mounted share.

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===== Using autofs =====

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=====Using autofs=====

Using [[autofs]] is useful when multiple machines want to connect via NFS; they could both be clients as well as servers. The reason this method is preferable over the earlier one is that if the server is switched off, the client will not throw errors about being unable to find NFS shares. See [[autofs#NFS Network mounts]] for details.

Using [[autofs]] is useful when multiple machines want to connect via NFS; they could both be clients as well as servers. The reason this method is preferable over the earlier one is that if the server is switched off, the client will not throw errors about being unable to find NFS shares. See [[autofs#NFS Network mounts]] for details.

==== Mounting from Windows ====

==== Mounting from Windows ====

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{{note|Only the Ultimate and Enterprise editions of Windows 7 and the Enterprise edition of Windows 8 include "Client for NFS"}}

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{{Note|Only the Ultimate and Enterprise editions of Windows 7 and the Enterprise edition of Windows 8 include "Client for NFS".}}

NFS shares can be mounted from Windows if the "Client for NFS" service is activated (which it is not by default).

NFS shares can be mounted from Windows if the "Client for NFS" service is activated (which it is not by default).

To install the service go to "Programs and features" in the Control Panel and click on "Turn Windows features on or off". Locate "Services for NFS" and activate it as well as both subservices ("Administrative tools" and "Client for NFS").

To install the service go to "Programs and features" in the Control Panel and click on "Turn Windows features on or off". Locate "Services for NFS" and activate it as well as both subservices ("Administrative tools" and "Client for NFS").

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Some global options can be set by opening the "Services for Network File System" (locate it with the search box) and right click on client->properties.

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Some global options can be set by opening the "Services for Network File System" (locate it with the search box) and right click on ''client > properties''.

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{{Warning|Serious performance issues may occur (it randomly takes 30-60 seconds to display a folder, 2 MB/s file copy speed on gigabit LAN, ...) to which Microsoft does not have a solution yet.[https://social.technet.microsoft.com/Forums/en-CA/w7itpronetworking/thread/40cc01e3-65e4-4bb6-855e-cef1364a60ac]}}

In order to get the most out of NFS, it is necessary to tune the {{ic|rsize}} and {{ic|wsize}} mount options to meet the requirements of the network configuration.

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=== Automatic mount handling ===

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This trick is useful for laptops that require nfs shares from a local wireless network. If the nfs host becomes unreachable, the nfs share will be unmounted to hopefully prevent system hangs when using the hard mount option. See https://bbs.archlinux.org/viewtopic.php?pid=1260240#p1260240

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Make sure that the NFS mount points are correctly indicated in {{ic|/etc/fstab}}:

The {{ic|noauto}} mount option tells systemd not to automatically mount the shares at boot. systemd would otherwise attempt to mount the nfs shares that may or may not exist on the network causing the boot process to appear to stall on a blank screen.

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Create the {{ic|auto_share}} script that will be used by ''cron'' to check if the NFS host is reachable,

A systemd unit file can also be used to mount the NFS shares at startup. The unit file is not necessary if NetworkManager is installed and configured on the client system. See [[#NetworkManger dispatch]].

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{{hc|/etc/systemd/system/auto_share.service|<nowiki>

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[Unit]

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Description=NFS automount

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[Service]

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Type=oneshot

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RemainAfterExit=yes

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ExecStart=/root/bin/auto_share

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[Install]

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WantedBy=multi-user.target

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</nowiki>}}

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Now enable {{ic|auto_share}}.

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==== NetworkManger dispatcher ====

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In addition to the method described previously, NetworkManager can also be configured to run a script on network status change.

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Enable and start the {{ic|NetworkManager-dispatcher}} service.

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The easiest method for mount shares on network status change is to just symlink to the {{ic|auto_share}} script:

Now when the wireless SSID "CHANGE_ME" goes up or down, the {{ic|nfs.sh}} script will be called to mount or unmount the shares as soon as possible.

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=== Configure NFS fixed ports ===

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{{Out of date|This section was originally refered to NFS version 3.}}

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If you have a port-based [[firewall]], you might want to set up a fixed ports. For rpc.statd and rpc.mountd you should set following settings in {{ic|/etc/conf.d/nfs-common}} and {{ic|/etc/conf.d/nfs-server}} (ports can be different):

* If you are setting up the Arch Linux NFS server for use by Windows clients through Microsoft's SFU, you will save a lot of time and hair-scratching by looking at [https://bbs.archlinux.org/viewtopic.php?pid=523934#p523934 this forum post] first !

Network File System (NFS) is a distributed file system protocol originally developed by Sun Microsystems in 1984, allowing a user on a client computer to access files over a network in a manner similar to how local storage is accessed.

Installation

Note: It is HIGHLY recommended to use a time sync daemon on ALL nodes of your network to keep client/server clocks in sync. Without accurate clocks on all nodes, NFS can introduce unwanted delays! The NTP system is recommended to sync both the server and the clients to the highly accurate NTP servers available on the Internet.

Client

Clients need nfs-utils to connect, and to avoid an approx 15 seconds delay with an accompanying error in dmsg that reads, "RPC: AUTH_GSS upcall timed out," users will need to start rpc-gssd service on any client.

Note: NFS4 servers do not need to run this service.

Mounting from Linux

Show the server's exported filesystems:

$ showmount -e servername

Then mount omitting the server's NFS export root:

# mount -t nfs4 servername:/music /mountpoint/on/client

/etc/fstab settings

Using fstab is useful for a server which is always on, and the NFS shares are available whenever the client boots up. Edit /etc/fstab file, and add an appropriate line reflecting the setup. Again, the server's NFS export root is omitted.

The rsize value is the number of bytes used when reading from the server. The wsize value is the number of bytes used when writing to the server. The default for both is 1024, but using higher values such as 8192 can improve throughput. This is not universal. It is recommended to test after making this change, see #Performance tuning.

timeo

The timeo value is the amount of time, in tenths of a second, to wait before resending a transmission after an RPC timeout. After the first timeout, the timeout value is doubled for each retry for a maximum of 60 seconds or until a major timeout occurs. If connecting to a slow server or over a busy network, better performance can be achieved by increasing this timeout value.

intr

The intr option allows signals to interrupt the file operation if a major timeout occurs for a hard-mounted share.

_netdev

The _netdev option tells the system to wait until the network is up before trying to mount the share. systemd assumes this for NFS, but anyway it is good practice to use it for all types of networked filesystems

Using autofs

Using autofs is useful when multiple machines want to connect via NFS; they could both be clients as well as servers. The reason this method is preferable over the earlier one is that if the server is switched off, the client will not throw errors about being unable to find NFS shares. See autofs#NFS Network mounts for details.

Mounting from Windows

Note: Only the Ultimate and Enterprise editions of Windows 7 and the Enterprise edition of Windows 8 include "Client for NFS".

NFS shares can be mounted from Windows if the "Client for NFS" service is activated (which it is not by default).
To install the service go to "Programs and features" in the Control Panel and click on "Turn Windows features on or off". Locate "Services for NFS" and activate it as well as both subservices ("Administrative tools" and "Client for NFS").

Some global options can be set by opening the "Services for Network File System" (locate it with the search box) and right click on client > properties.

Warning: Serious performance issues may occur (it randomly takes 30-60 seconds to display a folder, 2 MB/s file copy speed on gigabit LAN, ...) to which Microsoft does not have a solution yet.[1]

To mount a share using Explorer:

Computer > Map network drive > servername:/srv/nfs4/music

Mounting from OS X

Note: OS X by default uses an insecure (>1024) port to mount a share.

Either export the share with the insecure flag, and mount using Finder:

Go > Connect to Server > nfs://servername/

Or, mount the share using a secure port using the terminal:

# mount -t nfs -o resvport servername:/srv/nfs4 /Volumes/servername

Tips and tricks

Performance tuning

In order to get the most out of NFS, it is necessary to tune the rsize and wsize mount options to meet the requirements of the network configuration.

The noauto mount option tells systemd not to automatically mount the shares at boot. systemd would otherwise attempt to mount the nfs shares that may or may not exist on the network causing the boot process to appear to stall on a blank screen.

Create the auto_share script that will be used by cron to check if the NFS host is reachable,

Now when the wireless SSID "CHANGE_ME" goes up or down, the nfs.sh script will be called to mount or unmount the shares as soon as possible.

Configure NFS fixed ports

This article or section is out of date.

Reason: This section was originally refered to NFS version 3. (Discuss in Talk:NFS#)

If you have a port-based firewall, you might want to set up a fixed ports. For rpc.statd and rpc.mountd you should set following settings in /etc/conf.d/nfs-common and /etc/conf.d/nfs-server (ports can be different):